ruby net-imap up to 0.5.14 Net::IMAP command injection

Summaryinfo

A vulnerability labeled as critical has been found in ruby net-imap up to 0.5.14. Affected by this issue is the function Net::IMAP. Executing a manipulation can lead to command injection. This vulnerability is tracked as CVE-2026-47240. The attack is restricted to local execution. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in ruby net-imap up to 0.5.14 and classified as critical. This vulnerability affects the function Net::IMAP. The manipulation with an unknown input leads to a command injection vulnerability. The CWE definition for the vulnerability is CWE-77. The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a "raw data" argument that is sent verbatim after validation to prevent command injection. However, if a server does not support non-synchronizing literals, it may still be possible to inject arbitrary IMAP commands inside non-synchronizing literals. A server without support for non-synchronizing literals may interpret the "+}\r\n" as the end of a malformed command line and respond with a tagged BAD. In that case, the contents of the literal will be interpreted as one or more new pipelined commands, allowing a CRLF command injection attack to succeed. This affects criteria for #search and #uid_search; search_keys for #sort, #thread, #uid_sort, and #uid_thread; and attr for #fetch and #uid_fetch. This vulnerability is fixed in 0.6.5 and 0.5.15.

The advisory is available at github.com. This vulnerability was named CVE-2026-47240 since 05/19/2026. The exploitation appears to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1202 by the MITRE ATT&CK project.

Upgrading to version 0.5.15 or 0.6.4.1 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• ruby

Name

• net-imap

Version

• 0.5.0
• 0.5.1
• 0.5.2
• 0.5.3
• 0.5.4
• 0.5.5
• 0.5.6
• 0.5.7
• 0.5.8
• 0.5.9
• 0.5.10
• 0.5.11
• 0.5.12
• 0.5.13
• 0.5.14

License

• open-source

Website

• Product: https://github.com/ruby/net-imap/

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